Directions

1. Heat oven to 190C/170C fan/gas 5. Grease and line the bottom of a round 21cm loose-bottomed cake tin. With a wooden spoon or electric mixer, beat the butter and sugar together until smooth and a pale, creamy colour. In a separate bowl, sift together the flour, baking powder and cinnamon. One at a time, beat each egg into the butter mixture along with a tbsp of the dry mixture, then beat in the milk and fold in the rest of the dry ingredients until well combined.
2. In the bowl that contained the flour, mash the bananas until smooth and lump-free - whizz with the electric mixer if needed - then fold into the rest of the mixture until well combined. Spoon into the tin and smooth over the surface. Bake for 45-50 mins, until a skewer inserted into the centre comes out clean. Leave to cool for 5 mins, then remove from tin and continue cooling on a wire rack.
3. Use a serrated knife to cut the cake horizontally into 3 equal layers. Whip the cream until it forms stiff peaks, then chop the banana into small pieces and fold into the cream, along with the marshmallows. On the first layer, spread a generous covering of the dulche de leche, followed by half of the cream mixture. Sandwich the second layer on top and repeat. Thickly spread dulche de leche over the top of the cake, then arrange extra marshmallows around the edge.